/*
 * Copyright (c) 2005,2006 INRIA
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
 */
#ifndef EVENT_IMPL_H
#define EVENT_IMPL_H

#include "simple-ref-count.h"

#include <stdint.h>

/**
 * \file
 * \ingroup events
 * ns3::EventImpl declarations.
 */

namespace ns3
{

/**
 * \ingroup events
 * \brief A simulation event.
 *
 * Each subclass of this base class represents a simulation event. The
 * Invoke() method will be called by the simulation engine
 * when it reaches the time associated to this event. Most subclasses
 * are usually created by one of the many Simulator::Schedule
 * methods.
 */
class EventImpl : public SimpleRefCount<EventImpl>
{
  public:
    /** Default constructor. */
    EventImpl();
    /** Destructor. */
    virtual ~EventImpl() = 0;
    /**
     * Called by the simulation engine to notify the event that it is time
     * to execute.
     */
    void Invoke();
    /**
     * Marks the event as 'canceled'. The event is not removed from
     * the event list but the simulation engine will check its canceled status
     * before calling Invoke().
     */
    void Cancel();
    /**
     * \returns true if the event has been canceled.
     *
     * Checked by the simulation engine before calling Invoke().
     */
    bool IsCancelled();

  protected:
    /**
     * Implementation for Invoke().
     *
     * This typically calls a method or function pointer with the
     * arguments bound by a call to one of the MakeEvent() functions.
     */
    virtual void Notify() = 0;

  private:
    bool m_cancel; /**< Has this event been cancelled. */
};

} // namespace ns3

#endif /* EVENT_IMPL_H */
